drm/ttm: remove swap LRU v3

Instead evict round robin from each devices SYSTEM and TT domain.

v2: reorder num_pages access reported by Dan's script
v3: fix rebase fallout, num_pages should be 32bit

Signed-off-by: Christian König <christian.koenig@amd.com>
Tested-by: Nirmoy Das <nirmoy.das@amd.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/424009/